Wave movements in oceans and large lakes constitute an important source of energy which can be utilized by harvesting energy from the waves by means of wave power assemblies, also called wave energy converters, which are positioned or anchored at locations with suitable wave conditions.
A number of different types of wave energy converters for harvesting and converting wave energy into electrical power are previously known. One previously known type of wave energy converter is based on relative movement between, on the one hand, a buoyant body and a thereto attached so-called acceleration tube, and, on the other hand, a working piston reciprocable in the acceleration tube, wherein the relative movement is caused by wave movements in the body of water where the wave energy converter is anchored by means of one or several mooring lines for harvesting wave energy. The movement of the working piston can be used for driving, for example, a pump assembly, such as a double acting hydraulic pump or a hose pump, a hydraulic motor and/or a hydraulic turbine of an energy conversion system, which is disposed inside or adjacent to the buoyant body for producing electricity which can be transferred to an energy storage or electrical grid.
A disadvantage of the previously known wave energy converters with acceleration tubes and energy collecting devices in the form of hydraulic piston pumps is that the previously utilized pumps are usually designed as a cylinder with a through-going piston rod and require a large length of stroke to enable a sufficiently high pumping flow rate to be achieved, resulting in that the energy conversion assembly as a whole will require a large space. This usually results in a large weight of the wave energy converter and in that components of the energy conversion assembly will extend far beyond the side and/or above the buoyant body of the wave energy converter and thereby result in an undesirably large area exposed to the wind and an unfavourable weight distribution with a considerable part of the weight high up and/or beyond the outer contour of the buoyant body. The high weight may make placement and also maintenance of such a wave energy converter difficult, and the large area exposed to the wind and the unfavourable weight distribution can increase the risk of operational problems or breakdowns in strong winds.
Additional problems solved by the present invention will become evident from the following description.